Whilst it's very important to never, ever plagiarize (. take the credit for someone else's work), it's a good idea to see how others have approached the subject of your essay in the past. Whilst you don't need to copy the approach of others, the advantage of writing your own piece of work is that you can pick and choose the strengths you might have identified elsewhere, and use them in your essay. See how others have begun an essay on the subject, and challenge yourself to match or improve on it. Whether you do this or not, always remember to give appropriate references for this approach.